Gravity Falls Falls
by CrazyChick9091
Summary: The Doctor finds himself in a place he wants nothing to do with, but the TARDIS refuses to leave. The Pines twins discover that the sudden arrival of a mysterious alien foreshadows the doom of Gravity Falls.
1. Chapter 1

"CLARA!" the Doctor yelled from across the TARDIS controls. Sparks were shooting everywhere as the TARDIS shook and rumbled. "SHE'S GOING ON HER OWN! WE MAY BE IN FOR TROUBLE!"

Clara screamed as the seismic motions of the TARDIS flung her uncontrollably. "DOCTOR WHAT IS IT DOING?"

The Doctor grabbed a hold on a lever and pulled it as hard as he could. "LOOKS LIKE PARIS HAS TO WAIT! WE'RE ON A DETOUR!"

The TARDIS began to whoosh as the shaking began a patter of increasing and decreasing as they materialized. It slowly began to settle again, and Clara stood up and adjusted her hair and jacket. Then she walked over to the Doctor who was doing a quick check over the TARDIS.

"Blimey, what the hell was that?" Clara asked, trying to catch her breath.

"See, Clara, every once in a while the TARDIS decides where we go. It's pretty hard on her, but it's where we need to be, according to her," he said, popping his jacket into place.

"What's out there?" she asked, nervously excited.

"I guess we should find out." he said, walking over to the doors. Genuinely interested, as always, the Doctor slowly opened a door and took a glimpse outside.

He looked out, and saw a shabby-looking building nearby. Big letters on the roof spelled out "MYSTERY SHACK". The Doctor slammed the door shut immediately.

"What is it?" Clara asked. The Doctor said nothing. He rushed back to the controls and furiously tried to make the TARDIS leave. But it refused.

"Doctor, where are we?" Clara asked, more nervously this time, because she knows the Doctor would never leave someplace. At least, the Doctor she used to know.

He gave up on trying to get out of there. He slammed his hands down on the controls in frustration.

"Gravity Falls."

* * *

"Dipper, I swear! It wasn't the wind! You've been seeing crazy things all summer, but you don't believe this?" Mabel practically yelled at Dipper.

"Mabel, I'm not saying I don't believe you, it was just a 'What If' sort of thing. I'll go check the journal for anything that... whooshes." Dipper said, pulling out his journal. As he flipped through with the black-light, Mabel ran over and looked out of the window.

She was shocked to see a blue box just next to the forest.

"Dipper!"

"Mabel!" Dipper yelled at the same time.

"Dipper, there's a weird blue box outside!" she said.

"Does it look like this?" he asked, holding up the journal with the black-light.

The journal had a black-light drawing of a police box. Next to it, the author had written, **_TARDIS and the Doctor. TRUSTWORTHY, BUT A FORESHADOWING OF SOMETHING BAD._**

Mabel looked up at Dipper and nodded. Something terrible was about to happen in Gravity Falls.


	2. Chapter Two

"Doctor, what is so bad about this place that you can't stand to be here?" Clara asked, as the Doctor desperately pulled at the controls, hopeless.

"Gravity Falls is the most dangerous place on Earth. Maybe even the galaxy. Or the Universe. It's because of the people here that the Time War began. And they don't even realize it," The Doctor said, slamming the controls in defeat.

"Why would the TARDIS want us here so bad?" Clara asked.

"Because something they shouldn't mess with is going on. The TARDIS has been keeping an eye on this place. She knows I have to stop them, against my will," he said, sitting in his chair.

"Why don't you want to save them?" she asked softly.

"I can't."

* * *

Dipper and Mabel cautiously walked out of the Mystery Shack. They wanted to approach the box, but were terrified of who was inside.

"So there is some Doctor, who appears inside of a magic box, like a really bad present?" Mabel asked. Dipper rolled his eyes.

"I guess so. But it just says the Doctor. Doctor who?"

"Maybe the author never asked?" Mabel suggested.

"And what is a... TARDIS?" Dipper wondered aloud.

"I wonder if it has mustard..." Mabel said dreamily.

"Mabel. Focus. Something bad is going to happen, and that's why the Doctor is here. But what?"

Mabel was no longer focused on the TARDIS. She was instead frozen on the Shack, which had begun glowing very bright. Mabel screamed, and ran for the TARDIS.

"Mabel what-" Dipper turned around, and too, screamed. "Wait up, Mabel!"

Dipper and Mabel ran to the TARDIS, and the ground began to shake. They pounded on the door, hoping the Doctor would let them in. They screamed for help, and just when they felt hopeless, an older man swung open the door, and pulled the two inside, closing the door behind them. The twins' eyes grew wide, as they saw the very large control room.

"It's bigger on the _inside!_" Mabel gasped.

"Oh, how original, that one," the man said in a Scottish accent, sitting back down. Dipper instinctively started to observe the TARDIS.

"How is this possible?" Dipper asked rather loudly. The man stood up and clapped his hands together.

"Dimensional transcendentalism!" he said. "Or just Time Lord science, if you will."

"Time Lord..? So are you-" Mabel began to ask.

"I'm the Doctor. Just the Doctor. I'm the last Time Lord in this universe, and I travel through all of space and time, trying to make peace and protect all species. Yes, I am an alien, this is my spaceship/time machine," the Doctor announced proudly. Mabel closed her mouth.

"I'm Clara Oswald. His human friend," Clara said, waving to them.

Dipper looked up from the controls he was observing, "I'm Dipper Pines, and that's my twin sister, Mabel. I read a bit about you in this journal." Dipper held up the journal. The Doctor stared at it in horror.

"Where did you find that?" he asked. "Wait, it doesn't matter! You know this place is dangerous, right?"

"Dangerous? I thought it was just west of weird but..." Dipper trailed off.

"So you know about the bad things that are going to happen?" Mabel asked.

"Kids, Gravity Falls is the most dangerous town in the universe, or at least on Earth," he said. Dipper and Mabel looked at each other, a bit scared. Then Mabel gasped.

"There were people in the shack! Grunkle Stan, Soos, Wendy... we have to see if they're okay!" Mabel yelled, heading for the door. Dipper was right behind her. The Doctor was hesitant, while Clara headed for the door.

"You are going aren't you?" she asked. The Doctor pinched the bridge of his nose.

"I can't stop it. I'm going to try and save them, but in the end, I have to sacrifice the town to save the world. It's a fixed point in time. I can't help them."

"Doctor, if you can save and entire planet that once burned, you can save Gravity Falls." she said as she walked out the door. The Doctor sighed.

"I wish."


	3. Chapter 3

The twins ran from the TARDIS, and hurried back to the shack. Clara tailed close behind, but stopped when she noticed who was missing. She turned and saw the Doctor walking slowly behind.

"Come on then!" she yelled at him. The Doctor rolled his eyes and sighed loudly.

"What's wrong with you? These kids are in danger and they need _you_! Moping about isn't going to help them!"

The Doctor began to jog to catch up to them. "Get it together," Clara whispered to him, as they entered the Mystery Shack.

The Shack was a wreck. Souvenirs were thrown all about. Displays had toppled over. And there wasn't a human in sight. Dipper and Mabel went poking around for anyone who may be hiding. Or injured.

"Looks like a bad tourist trap," The Doctor stated aloud, as he scanned the area with the sonic.

"Oh, it is," Dipper said, pushing a T-shirt rack upright. They cleared the area up, and there wasn't a sign of anyone.

"Hold on! I've got something!" the Doctor called, as the sonic gave off a strange, whirring noise. "Strange readings... This way!" the Doctor cried, running out to the back. Clara followed.

"Dipper, what do you think happened? To Stan, Soos, and Wendy? They were all here..." Mabel asked, as they walked to the back.

"I have no idea, Mabel. Let's just hope they're okay."

The Doctor stopped at the soda machine. Dipper and Mabel looked puzzled.

"It was the soda machine?" Mabel asked.

"No, it's what's behind the soda machine." the Doctor replied.

"Behind? But there's-" Dipper was cut off by the sonic's buzzing, and the secret door being revealed. "A secret base?"

A scream rang out from inside. "Let's go!" the Doctor said, running inside the passage. The others followed close behind.

The entered a room with an enormous triangular portal behind a glass wall. It was flashing and clearly activated. And there were people inside. Dipper first noticed two familiar figures.

"Wendy! Soos!" he cried, running for the portal.

"Wait!" the Doctor yelled. But Dipper was already through the door, and on the other side.

"Dipper!" Wendy cried, "Run!" Dipper stopped short. He felt a figure behind him, and then he couldn't move.

The Doctor and Clara were trying to get into the room, but a girl had locked the door. Then another girl, with short red hair and dark clothes, snatched Dipper. She took him through the portal.

"Stop!" Mabel cried. She ran up to the glass. Then she saw another girl. Herself. But it wasn't herself. This girl had a blue jacket and a short grey skirt. Her headband had a green stone that looked... familiar. The girl reminded her of... Gideon?

The girl turned, and grinned. Then a boy was by her side, with a blue button-down and an amulet just like Gideon's. His hair was slicked back, and he had a big dipper birthmark on his forehead.

"...Dipper?" Mabel whispered. But the girl, who must have been her, waved her fingers and jumped into the portal with the boy, who must have been Dipper.

"They've taken him," the Doctor whispered.

"They looked just like these twins," Clara said. "Who were they, Doctor?"

"The twins, Clara. That _was_ them. But in reverse."

"So they're like Gideon?" Mabel asked, staring through the glass. "Wendy, Soos, Dipper... They took them. And they're evil."

"...Yes," the Doctor said.

"How can we save them?" she asked.

"Well, the portal's still running. We could-" Clara was cut off.

"I wouldn't," said a voice from the shadows. "It's too dangerous, and there might not be enough for the trip back. Assuming you'd even survive."

Mabel turned around. "Grunkle Stan?"

A tired old man, in a tank and boxers, who looked beaten and defeated stepped from the shadows. "I'm sorry."

"Wha- did _you _open the portal?" Mabel asked. She stepped away from the bruised man.

"I'm sorry, I didn't think this would happen," he said, a look of pain in his eyes.

"YOU opened the portal? They TOOK Dipper! He could be dead!" Mabel screamed, tears in her eyes.

"Mabel, I-"

"No! He's my brother! My best friend! Without him... I don't know what to do! He would know what to do. I'm... too stupid. I should've ran in there. They should've taken me," Mabel fell to her knees, and cried.

"Mabel, you aren't stupid. We'll find Dipper. It's be okay," Clara said, putting her arm around Mabel. The Doctor looked away from the crying girl. Then he turned back to Stan.

"You stupid, ignorant man! You knew about the dangers and you still opened the portal!?" he yelled.

"Look, I just... I just wanted my," Stan paused, and looked down at Mabel. "I just wanted my brother back."


	4. Chapter 4

Dipper stirred, his eyelids fluttering as his eyes began to focus on his surroundings. He was dizzy, and his head throbbed slightly. He soon found he was in a dusty, dark room. He was kneeling in a corner, his hands and feet bound by ropes. A feminine figure walked into the dim light.

"...M-Mabel?" he whispered, looking up at the girl with long, wavy brown hair and a blue blazer jacket.

"Not exactly, sweetheart," she said, with an evil smirk on her face. She approached Dipper, grabbed his forearm, and yanked him to his feet.

"Who- who are you then?" Dipper asked, trying to stand up straight. She pushed him against the wall.

"Mabel. I'm Mabel. You just don't seem to get it. We're in a dimension parallel to yours. Everyone is here, but they're opposite of your petty versions," she kicked him in the gut.

"Your precious sister might be sweet, kind, lovable, and _stupid_. I'm cold, cunning, and sharp. I'm not nearly as merciful, either." She stomped on Dipper's wrist, and it was followed by a sickening crunch.

Dipper cried out in pain, and she laughed at him. "You can just call me Star, since you have your own Mabel." Star said, staring down at him. "Not that you'll ever see her again."

Star kicked Dipper in the shin, and then locked him alone in the room. Or at least, he thought he was alone.

"...Is she gone?" a girl whispered. Dipper was in so much pain he was too occupied with writhing in pain.

A blonde girl, about Dipper's age, stepped from the shadows. She wore her hair up in a messy ponytail. The girl wore a T-shirt that was one size too big, and a baggy purple jacket. Her jeans were dirty and worn, but were not nearly as bad as her beaten pair of Chucks. She tugged nervously at the hem of her shirt as she got near Dipper. He looked up at her, and she stared at him with bright blue eyes.

"Pacifica..?" Dipper drew out slowly as she knelt down next to him. She nodded quietly.

"Mabel is really terrible. But you should meet her brother Tyrone. He's awful," Pacifica said, and she carefully untied Dipper's wrists. His broken wrist shifted to the side, and Dipper's eyes watered in agony. "Sorry."

"Tyrone?" Dipper asked, already knowing deep inside the answer.

"Tyrone is Mabel- sorry, Star's twin brother. He looks exactly like you, but more sinister."

Pacifica tossed aside the rope that once bound Dipper's wrists. She then helped him sit upright, and began to untie his ankles.

Dipper looked at Pacifica, intrigued. He asked her, "So, what are you doing in here, anyway?"

She looked at him, and told him the story of Reverse Falls.

_In this world, this dimension. Gravity Falls is owned by The Mystery Twins. Their great-uncle Stan was an evil man, but one day, he vanished, never to be heard from again. The twins own the town, and boy do they. They use their psychic powers to control everyone in the town, and if not their powers, it's fear and manipulation. They have a whole gang of teens who do whatever they say. Mabel handles most of the arm-twisting and commands, while Tyrone works kind of- underground. He'll tell Mabel if anyone is out of line, and people rarely see him outside the Shack. _

_Grenda is a strong and very brutal girl that Mabel uses to push rebels back in line, or she just has Grenda beat people because she can. _

_Candy is a super-smart techie that usually blogs about anyone and everyone's problems. She's Tyrone's informant, and a lot of his dirt on people comes from her. _

_Wendy is like their personal assistant. If either one of them is busy, Wendy is usually there to fill in. You can sometimes bribe your way out of a Grenda-beating if it's Wendy giving the order. She also handles most of the darker dirty work, like when she kidnapped you._

_Soos a really handsome and intelligent jerk. He's Tyrone's only friend, next to Mabel, and is usually running the Shack. He can con you out of twice the cash you were supposed to pay on gift-shop items._

_Their little gang had been waiting for years for the portal to open. And when it did, they were more than ready. They plan to enslave the whole worlds of both dimensions. But we have an underground rebellion._

_Gideon is my best friend and a really smart kid. He and I infiltrated the Shack last month and we've been secretly living inside. We've been really good about staying out of Tyrone and Candy's eyeline. _

_Robbie is a really sweet guy. He's been dating Wendy for awhile, but he still helps us with anything he overhears when he's out with Wendy. He's really useful._

_Old Man McG is our leader. He's the only one who can see into the other dimension. He's a pretty hardcore guy, but he'll want to help you get home._

_Stanley Pines is actually from your dimension. He said he opened the portal by mistake almost thirty years ago. He won't talk much to anyone, but we did rescue him from Stan before he went missing. We think Stanley is permanently traumatized, and he can't really help us._

_But we do know that we can stop The Mystery Twins if we can rally your dimension before it's too late. Mabel and Tyrone are scheming, but it could take awhile. But it could also take no time at all. _

"So, will you come join us?" Pacifica asked, brushing stray blonde hair from her eyes. Dipper winced, but he nodded curtly. Pacifica smiled at him, and pulled the rope that once bound his ankles away.


	5. Chapter 5

**Short chapter, but I hope you enjoy!**

"So, your twin got wrapped up in this portal and got stuck on the other side?" a still sniveling Mabel asked.

"Thirty years ago, I think. I told him it was too dangerous and stupid. But he just went ahead anyway... I still miss the guy," Stan said, rubbing his nose.

"And it's taken you this long to reopen it?" the Doctor asked.

"The second it opened, chaos reared its ugly head. Bill came and tried to steal the journals, and The Society of the Blind Eye hid them and wiped everyone's memory of their locations. I found the first one, Gideon found the second, and Dipper, the third," Stan said. The Doctor nodded inquisitively.

"And Bill isn't here this time? Who is Bill, exactly?"

"An evil being of pure... well, evil. He has dark powers beyond comprehension. And he knows _everything_."

The Doctor looked at Stan in horror. "Is his true form-"

"He appears as a flat yellow pyramid with a bow tie and top hat. One eye," Stan said.

"The Nightmare Child!" the Doctor gasped. He began pacing furiously, and he pressed his hands into his temples.

"Doctor, who is the Nightmare Child?" Clara asked.

"It was one of the most deadly things to fight in the Time War. It could crush whole fleets, and it swallowed Davros's command ship. It was far too intelligent to defeat. And... it's here?" he turned to Stan.

"Bill? He's been here for years. It's his fault we're living like this," Stan said. The Doctor swore vulgarly.

"Doctor!" Clara scolded, looking down at Mabel. Mabel laughed weakly.

"Don't worry, I've been living with Stan all summer. There's more important things than worrying about my vocabulary," she said.

"She's not wrong," Stan said, looking slightly sheepish. Clara laughed quietly to herself.

"Okay, so now that I have just gotten a better perspective on why I hate this place, we need to reopen the portal," the Doctor said, moving to the controls.

"You realize that machine takes a monstrous amount of power to operate? And don't forget the cool down," Stan said.

"I... Of course I knew that," the Doctor took a step back from the controls. "How long's that gonna take?"

"A week at best," Stan said with a tone of disappointment. "Don't wanna damage the fabric of time with opening it too much."

The Doctor grimaced, having a horrible flashback. "Yeah, we'd better wait."

"But a week!? Dipper, Wendy, and Soos are in there!" Mabel cried.

"I have a feeling there are bound to be people there to save them," Clara said, reassuringly.

"You think so?" Mabel asked. Clara nodded.

"There's always a good guy to help out."


End file.
